geologist
n. countablen. a scientist who studies the Earth, including the rocks it is made of and how they change over time. They look at things like mountains, volcanoes, and fossils to understand the planet's history.
n. a scientist who studies the solid, liquid, and gaseous matter that constitutes the Earth and other terrestrial planets, as well as the processes that shape them. Focuses on the physical structure and substance of the Earth, its history, and the processes which act on it.
The geologist examined the rocks to find out how old they were.
After the earthquake, a geologist arrived to study the fault line and assess the risk of future tremors.
By analyzing the mineral composition of the core samples, the geologist was able to reconstruct the environmental conditions that existed in the region millions of years ago.
From geology + -ist.